IT1252 Digital Signal Processing B.E Question Bank : niceindia.com
Name of the College : Noorul Islam College of Engineering
University : Anna University
Degree : B.E
Department : Computer Science and Engineering
Subject Code/Name : IT 1252 –
Digital Signal Processing
Year : IV
Semester : VII
Document Type : Question Bank
Website : niceindia.com
Download :https://www.pdfquestion.in/uploads/ni…Processing.pdf
Digital Signal Processing Question Paper
1. What is a continuous and discrete time signal? :
Ans :
Continuous time signal :
A signal x(t) is said to be continuous if it is defined for all time t. Continuous time signal arise naturally when a physical waveform such as acoustics wave or light wave is converted into a electrical signal. This is effected by means of transducer.(e.g.) microphone, photocell.
Related : Noorul Islam College of Engineering CS1304 Microprocessor & Microcontrollers B.E Question Bank : www.pdfquestion.in/2919.html
Discrete time signal :
A discrete time signal is defined only at discrete instants of time. The independent variable has discrete values only, which are uniformly spaced. A discrete time signal is often derived from the continuous time signal by sampling it at a uniform rate.
2. Give the classification of signals? :
Ans :
**Continuous-time and discrete time signals
**Even and odd signals
**Periodic signals and non-periodic signals
**Deterministic signal and Random signal
**Energy and Power signal
3. What are the types of systems? :
Ans :
**Continuous time and discrete time systems
**Linear and Non-linear systems
**Causal and Non-causal systems
**Static and Dynamic systems
**Time varying and time in-varying systems
**Distributive parameters and Lumped parameters systems
**Stable and Un-stable systems.
4. What are even and odd signals? :
Ans :
Even signal :
continuous time signal x(t) is said to be even if it satisfies the condition x(t)=x(-t) for all values of t.
Odd signal :
he signal x(t) is said to be odd if it satisfies the condition x(-t)=-x(t) for all t.
In other words even signal is symmetric about the time origin or the vertical axis, but odd signals are anti-symmetric about the vertical axis.
5. What are deterministic and random signals? :
Ans :
Deterministic Signal :
deterministic signal is a signal about which there is no certainty with respect to its value at any time. Accordingly we find that deterministic signals may be modeled as completely specified functions of time.
Random signal :
random signal is a signal about which there is uncertainty before its actual occurrence. Such signal may be viewed as group of signals with each signal in the ensemble having different wave forms
(e.g.) The noise developed in a television or radio amplifier is an example for random signal.
7. What are the operations performed on a signal? :
Ans :
Operations performed on dependent variables :
Amplitude scaling : y (t) =cx (t), where c is the scaling factor, x(t) is the continuous time signal.
Addition : y (t)=x1(t)+x2(t)
Multiplication y (t)=x1(t)x2(t)
Differentiation : y (t)=d/dt x(t)
Integration (t)
Operations performed on independent variables :
**Time shifting
**Amplitude scaling
**Time reversal
8. What are elementary signals and name them? :
Ans :
The elementary signals serve as a building block for the construction of more complex signals. They are also important in their own right, in that they may be used to model many physical signals that occur in nature.
There are five elementary signals. They are as follows :
**Unit step function
**Unit impulse function
**Ramp function
**Exponential function
**Sinusoidal function
9. What are the properties of a system? :
Ans :
Stability : A system is said to be stable if the input x(t) satisfies the condition(t)
Memory : A system is said to be memory if the output signal depends on the present and the past inputs.
Invertibility : A system is said to be invertible if the input of the system con be recovered from the system output.
Time invariance : A system is said to be time invariant if a time delay or advance of the input signal leads to an identical time shift in the output signal.
Linearity : A system is said to be linear if it satisfies the super position principle
i.e.) R(ax1(t)+bx2(t))=ax1(t)+bx2(t)
10. What is memory system and memory less system? :
Ans :
A system is said to be memory system if its output signal at any time depends on the past values of the input signal. circuit with inductors capacitors are examples of memory system..
A system is said to be memory less system if the output at any time depends on the present values of the input signal. An electronic circuit with resistors is an example for memory less system.
11. What is an invertible system? :
Ans :
A system is said to be invertible system if the input of the system can be recovered from the system output. The set of operations needed to recover the input as the second system connected in cascade with the given system such that the output signal of the second system is equal to the input signal applied to the system. H-1{y(t)}=H-1{H{x(t)}}.
12. What are time invariant systems? :
Ans :
A system is said to be time invariant system if a time delay or advance of the input signal leads to an idenditical shift in the output signal. This implies that a time invariant system responds idenditically no matter when the input signal is applied. It also satisfies the condition R{x(n-k)}=y(n-k).